1. Field of the Invention
The present invention relates generally to apparatus for charging raw batch material into a glass melting furnace and more particularly to a seal arrangement for a batch charger.
The invention is used with chargers such as those disclosed in U.S. Pat. Nos. 5,073,183; 4,197,109 and 3,780,889, all of which are commonly owned with the present application. These patents disclose batch chargers for continuous glass melting furnaces of the type having burners mounted along the opposed sidewalls and a batch charger located adjacent an end wall in an area referred to as the doghouse. A continuous glass melting furnace of this type comprises a large rectangular tank which contains a bath of molten glass. Raw batch material is continuously supplied to the upper surface of the bath by a batch charger. The doghouse area may extend along a substantial part of the width of the furnace end wall which may be up to 20 to 30 feet. A plurality of batch chargers may be arranged in the doghouse area in side-by-side relationship along the furnace end wall. The doghouse area of a furnace end wall typically includes a suspended wall located inwardly from the furnace end wall and having its lower end spaced above the upper edge of the furnace end wall to provide an access opening therebetween. The access opening provided in the doghouse area extends downwardly opening into the furnace above the upper surface of the molten glass in the furnace onto which raw batch material is charged. The raw batch material will initially float on the upper surface of the molten glass and melt as it moves into the furnace away from the furnace end wall.
Conventional batch chargers include a reciprocable, water cooled, generally U-shaped charger plate that extends downwardly at an adjustable angle into the doghouse area of the furnace end wall. The charger plate is located below the discharge opening of a material supply hopper so that as the charger plate moves forward into the furnace from the retracted position, raw batch material is deposited from the hopper discharge opening in a layer onto the upper surface of the bottom wall of the charger plate. Simultaneously, the nose or forward edge of the charger plate pushes a previously deposited layer of batch material which is floating on the upper surface of the molten glass bath under the suspended wall at the end of the doghouse away from the furnace end wall into the melting zone of the furnace. As the charger plate retracts, the layer of batch material which has been deposited on the upper surface of the bottom wall of the charger plate is contacted by a seal member located at the rear wall of the hopper and is forced off the forward edge of the charger plate onto the open area on the upper surface of the molten glass bath from which the previous charge has been cleared. This reciprocating cycle of the charger plate is continuously repeated to maintain a substantially constant level or blanket of batch material on the upper surface of the molten glass bath, and hence, the level of the molten glass bath in the furnace is continuously maintained as glass is removed from the furnace.
When the charger plate is retracted in prior art arrangements, batch material remaining thereon could bypass the hopper in the spaces between the sidewalls of the hopper and the sidewalls of the U-shaped charger plate. This material accumulates behind the hopper and creates a problem during the continuous reciprocal motion of the charger plate.
The present invention solves the problem of accumulated batch material behind the hopper by providing an arrangement which prevents batch material from being drawn behind the hopper when the charger plate is retracted to receive a fresh batch of material from the discharge opening of the hopper. Additionally, the present invention provides for easy adjustment and replacement of the seal member which is necessary on a reoccurring basis.